Annealing behavior of barriers in ion-implanted LiNbO3 and LiTaO3 planar waveguides

We formed planar waveguides in LiNbO3 and LiTaO3 crystals by megaelectron v olt He-ion implantation. The dark modes of both waveguides are measured and their refractive-index profiles are described according to the parameteriz ed index profile reconstruction method. The extraordinary indices of both i on-implanted waveguides exhibit quite different profiles. We compare the th ermal stability of barriers in ion-implanted LiNbO3 and LiTaO3 waveguides b y annealing at different temperatures. The results show that the barrier in a LiTaO3 planar waveguide has higher thermal stability than that in a LiNb O3 waveguide. The experiments also show that annealing at a temperature hig her than 400 degrees C results in recrystallization of the barrier. (C) 199 9 Optical Society of America. OCIS codes: 130.2790, 130.3120.